[LU-12345] backport - ext4: optimize ext4_find_delalloc_range() in nodelalloc mode

• Type: Bug
• Resolution: Fixed
• Priority: Major
• Fix Version/s: Lustre 2.13.0, Lustre 2.12.5
• Labels: patch
• Severity: 3
• Assignee: Artem Blagodarenko (Inactive)
• Reporter: Artem Blagodarenko (Inactive)

Description

From 8c48f7e88e293b9dd422bd8884842aea85d30b22
..
We found performance regression when using bigalloc with "nodelalloc"
(1MB cluster size):
1. mke2fs -C 1048576 -O ^has_journal,bigalloc /dev/sda
2. mount -o nodelalloc /dev/sda /test/
3. time dd if=/dev/zero of=/test/io bs=1048576 count=1024
The "dd" will cost about 2 seconds to finish, but if we mke2fs without
"bigalloc", "dd" will only cost less than 1 second.
 
 

Issue Links

• is related to: LU-12103 Improve block allocation for large partitions
• is related to: LU-16286 nodelalloc optimization is missing for RHEL8 kernels causing performance drop